However, although medical management using methotrexate is used commonly, there is no solid consensus regarding dose protocol. Currently, there are three methotrexate protocols for the treatment of an ectopic pregnancy, "multi-dose", "single-dose", or "two-dose". Among them, the multi-dose protocol includes the administration of 4 methotrexate doses alternating with leucovorin (rescue regimen). As a result of the multiple dosing of methotrexate, side effects are more common. In contrast, the advantages of the single-dose protocol include elimination of a rescue regimen, lower incidence of adverse effects, and better compliance. However, the single-dose protocol was found to be associated with a considerably lower success rate as compared with the multi-dose protocol (88% versus 93%) in a recent meta-analysis. The two-dose protocol, which it balances efficacy and safety/convenience, was described as a cross between the multi-dose and single-dose protocols.